An organic light-emitting device, namely, an organic light-emitting diode (OLED), also called an organic electroluminescence display, has an all-solid-state feature, good mechanical property, and strong shock resistance; and uses a plastic or polyester film or sheet as a substrate. An OLED screen can be made thinner, and even can be folded or rolled up, to achieve flexible soft screen display.
With the development of display technology, research and development engineers continuously make improvements in flexible display apparatuses that can be folded or rolled up. Compared with traditional rigid display apparatuses (that is, display apparatuses fabricated on an inflexible substrate such as glass), the flexible display apparatuses have many advantages such as lighter weight, smaller size, more convenient carrying, higher impact resistance, and stronger shock resistance.
However, when the flexible display apparatus is bent, many defects can occur at the interface of the multilayer structure because of differences in Young's modulus between the layers, affecting the device performance. A thin film transistor is an important functional device in the flexible display apparatus, and therefore its performance has a significant influence on the overall performance of the flexible product. In the prior art, the thickness of a high-hardness film layer is reduced generally by optimizing the device structure, to make the hardness of adjacent structural film layers as close to each other as possible, thus reducing the damage to the functional layer. However, the thickness change of the material in different layers of the thin film transistor may have an effect on the performance of the thin film transistor, so that a final product fails to achieve its desired effect.
Therefore, there is an urgent need to provide a method for preventing damage to a thin film transistor device during bending.